If you accept the proposition that it's possible for a microbe to secrete a protein or something into the bloodstream that causes you to prefer a certain type of food (and keep in mind that we already have evidence of biologically-driven food cravings, e.g. in pregnant women), then there's a good argument that evolutionary pressure would eventually cause gut flora that could help deliver its own preferred food source to predominate in human digestive systems.
In either case, I can't work out how specifically thai food would make you do either consistently.
In Australia it seems most people think of Pad Thai or Green Curry when it comes to thai food.. I'm not sure what the US "default" for thai food is?
I personally really like a good Lat na, but what I'm served is often noodles in a thick, chicken flavored grease (rather than stock or gravy).
Even with a Thai owner and/or chef, it seems in most countries, there is some degree of adapting each dish to the local environment. This may be because of available ingredients or because of local tastes.
Thai people do love to fry things (both shallow and deep), but in my experience that doesn't necessarily translate into particularly oily sauces. In my time here I've once had a green curry that actually had a visible layer of oil (about 1cm thick) floating on top of the sauce itself, but that is definitely not the norm!
In terms of butter, that is very surprising to me. The only thing I've ever seen butter used for here is to fry fresh roti (which are then served with condensed milk and banana or chocolate or sugar or whatever you want)..
You might have some allergy or food intolerance to a common ingredient. Then directed selection of your gut biome won't help.
(I love Thai food myself, but it is a bit dangerous to even go into restaurant, since I'm really allergic to nuts and peanuts. I can't even be in the same room as peanuts.)